Why some birds are smarter than others?: They have larger brain structures that mediate information

University of Alberta neuroscientists have identified the neural circuit that may underlay intelligence in birds, according to a new study. The discovery is an example of convergent evolution between the brains of birds and primates, with the potential to provide insight into the neural basis of human intelligence.

“An area of the brain that plays a major role in primate intelligence is called the pontine nuclei,” explained Cristian Gutierrez-Ibanez, postdoctoral fellow in the Department of Psychology. “This structure transfers information between the two largest areas of the brain, the cortex and cerebellum, which allows for higher-order processing and more sophisticated behaviour. In humans and primates, the pontine nuclei are large compared to other mammals. This makes sense given our cognitive abilities.”

Birds have very small pontine nuclei. Instead, they have a similar structure called the medial spiriform nucleus (SpM) that has similar connectivity. Located in a different part of the brain, the SpM does the same thing as the pontine nuclei, circulating information between the cortex and the cerebellum. “This loop between the cortex and the cerebellum is important for the planning and execution of sophisticated behaviours,” said Doug Wylie, professor of psychology and co-author on the new study.

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“The SpM is very large in parrots. It’s actually two to five times larger in parrots than in other birds, like chickens,” said Gutierrez. “Independently, parrots have evolved an enlarged area that connects the cortex and the cerebellum, similar to primates. This is another fascinating example of convergence between parrots and primates. It starts with sophisticated behaviours, like tool use and self-awareness, and can also be seen in the brain. The more we look at the brains, the more similarities we see.” Paper.(open access) – Cristián Gutiérrez-Ibáñez, Andrew N. Iwaniuk, Douglas R. Wylie. Parrots have evolved a primate-like telencephalic-midbrain-cerebellar circuit. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-28301-4 More.

Actually, the researchers did not find similarities in the brains of birds and primates, as suggested in the release. They found quite different brain structures that mediate the same tasks. The convergence is of intelligence alone. Usually, “convergent evolution” refers to convergence of structures, not just of goals. They’ll need a lot of luck to come up with much insight into human intelligence, as they hope, because what they have found here is simply one reason that some birds are as capable of tasks requiring intelligence as some primates are.